The present invention relates to Reed-Solomon codes and more particularly to decoding of such codes.
Reed-Solomon codes are the most powerful random error correcting codes now known. Since these codes form a class of Bose-Chaudhuri-Hocquenghem (BCH) codes, general BCH decoding techniques can be applied to them. A typical BCH decoding procedure is to first calculate the error syndromes, then find the error location polynomial, thereafter search for the roots of the error correction polynomial and finally calculate the errors and make the actual correction or corrections. This specification deals with the finding of the error location polynomial. General solutions to this problem are known such as those described in Chapter 9 of Error-Correcting Codes, Second Edition, by Peterson and Weldon, published in 1972 by The MIT Press, Cambridge, Massachusetts. It is also generally known that it is possible to obtain particular solutions for specific applications and it has been suggested in Bossen et al, U.S. Pat. No. 3,893,071 that where a code is capable of correcting one or more errors to first check to see if a single error has occurred and if it has, correct for it. This is done on the basis that most errors are single errors and checking for multiple errors would be time consuming. However with Reed-Solomon codes the number of calculations needed to be made to find the error location polynomial in this manner is significant.